The present invention relates generally to mechanical clutches and more particularly to an improved dog clutch. A dog clutch is used for positively coupling together two shafts including a driven coupling-part and a driving coupling-part, whereby each coupling-part incorporates axially extending drive claws with recesses located therebetween so that the drive claws of one coupling-part will engage in the recesses of the other coupling-part when they are in the coupled state.
The dog clutch being considered here is known in the form of a disengageable and a non-disengageable clutch. It is also referred to as a longitudinally compliant coupling since it can compensate for changes in the axial length of the shafts caused by heat for example or, due to unpredictable constructional inaccuracies. Couplings of this type can disengage when in use but can only be re-engaged when stationary. In the case of a disengageable dog clutch, the two parts of the coupling are centered by means of a ring upon which the interengaging drive claws slide.
Couplings of this type are employed, in particular, when the diameter of the shafts and thus the torques being transferred therebetween are relatively large. One field of application therefor is that of agricultural machines. Thus, for example, in the case of a so-called high speed coupling for mechanically coupling a tractor to an agricultural machine, it is known to couple up the drive train extending between the tractor and the machine by means of a dog clutch. To do this, it is necessary to center the end of the axle to be coupled. The two parts of the coupling are provided with centering surfaces on their opposing faces for this purpose.
The previously known forms of centering require additional components or must be of special design thereby increasing the costs. Moreover, they are not particularly suitable for agricultural machines since they are particularly prone to failure over time, due to the working conditions.
An object of the invention is to provide a dog clutch of the type described with a simplified construction.
Another object is to provide a dog clutch according to the foregoing object and such that no additional components are required for centering the coupling-parts, i.e. such that expensive, specially designed components are not needed in order to meet the demands imposed by an agricultural environment.
Yet another object is to provide a dog clutch with a self-centering function.